This invention relates generally to semiconductor device fabrication, and more particularly the invention relates to the fabrication of a microwave field-effect transistor (FET) having a gate with submicron length.
The operating frequency of an FET for use in a microwave integrated circuit is dependent on the length of the gate electrode between the source and drain regions of the FET. More particularly, gate lengths of from 0.1 to 0.5 micron are required for device operation at higher microwave frequencies.
Heretofore, to achieve uniform gate lengths in the submicron range, electron beam lithography has been required. E-beam processing is relatively slow and requires expensive equipment. The present invention is directed to a process for uniformly fabricating submicron length gates without the need for electron beam lithography and the costs attendant therewith.